Monolithic LED Chip Series Sub-LEDs High Voltage Low Current

Solution Overview

Problem

Conventional LED chips operating at high current and low voltage require expensive and bulky driver circuitry, and achieving high light output in a compact form factor is challenging due to the need for multiple LED packages with 'dead space' between them, limiting the ability to shape the light output effectively.

Innovation Solution

A monolithic LED chip design featuring multiple sub-LEDs connected in series on a single submount, allowing for high voltage and low current operation while maintaining a compact size, with sub-LEDs being densely packed to maximize active emission area and using conductive interconnects and insulating features for efficient light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If multiple LED packages are mounted on a circuit board to achieve high light output, then the total luminous flux increases, but the device size increases and 'dead space' between packages limits compactness

Engineering Contradiction:

Improvetotal luminous fluxVSAvoiddevice size

Core Design Contradiction:

Illumination intensityVSArea of stationary object

Solution Approach 1:

Multiple LED junctions are integrated onto a single LED chip substrate, merging what would traditionally be separate LED packages into one unified device. This eliminates the dead space between packages while maintaining high total luminous flux through the combined output of multiple junctions on the same chip.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a two-dimensional array of separate LED packages on a circuit board to a three-dimensional integration where multiple LED junctions are stacked or arranged vertically on a single chip substrate, effectively utilizing the vertical dimension to pack more light-emitting elements into a smaller footprint.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If single LED chips operate at high current to achieve high light output, then luminous flux increases, but expensive and bulky driver circuitry is required

Engineering Contradiction:

Improveluminous fluxVSAvoiddriver circuitry

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The LED chip is divided into multiple independent LED junctions that can be electrically connected in series. This segmentation allows the total luminous flux to be achieved through multiple lower-current junctions rather than one high-current junction, thereby reducing the complexity and size of the required driver circuitry.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the electrical operating parameters by connecting multiple LED junctions in series, which increases the operating voltage while reducing the operating current compared to a single high-power LED junction. This parameter transformation enables the use of simpler, less bulky driver circuitry that is better suited for high-voltage, low-current operation.

Inventive Principle:

Principle #35Parameter changes

3Stress or pressure

If multiple LED packages are used to achieve high voltage operation, then voltage increases, but the number of components and assembly complexity increase

Engineering Contradiction:

Improveoperating voltageVSAvoidnumber of components

Core Design Contradiction:

Stress or pressureVSDevice complexity

Solution Approach 1:

Multiple LED junctions are integrated onto a single LED chip substrate, merging what would traditionally be separate LED packages into one unified device. This eliminates the dead space between packages while maintaining high total luminous flux through the combined output of multiple junctions on the same chip.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The LED chip is divided into multiple independent LED junctions that can be electrically connected in series. This segmentation allows the total luminous flux to be achieved through multiple lower-current junctions rather than one high-current junction, thereby reducing the complexity and size of the required driver circuitry.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design enables efficient high voltage and low current operation with reduced driver circuitry size, increased system efficiency, and improved light output in a compact form factor, while also providing fault tolerance and reduced costs per lumen.

Implementation Method 1

Light emitting diodes (LED or LEDs) are solid state devices that convert electric energy to light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a reflective layer on the submount

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS9093293B2High voltage low current surface emitting light emitting diode

Publication Date: 2015.07.28 CREELED INC

AI summary

A light emitting diode chip includes a submount, a reflective layer on the submount, an insulating layer on the reflective layer opposite the submount, and a plurality of sub-LEDs on the insulating layer. Each of the sub-LEDs includes a first face adjacent to the submount and a transparent contact on the first face between the sub-LED and the insulating layer and electrical interconnects between adjacent ones of the sub-LEDs.